VetTech

It started when the weather was cold, but my car has always had trouble in cold weather, so I didn't think much of it. It hasn't stopped, though, even though it's warmed up, and if anything, it has gotten worse. When I start the car, it sputters (the same sound as if you are about to run out of gas), and doesn't speed up very well when I push the gas pedal. As I push the gas pedal, it also has a clicking sound and the car moves forward in a jerking motion.

Also, while I'm asking, the car doesn't like to give me my key back when it's cold (it gets stuck in the ignition). Any ideas would be appreciated.